Hydrochloric Acid → (2S)-2-Methylpiperidine-1-carbonyl chloride

Participants

Reaction Steps

To a pale yellow solution of triphosgene (742 mg, 2.50 mmol) and pyridine (0.404 mL, 5.00 mmol) in dry DCM (10 mL) at 10° C. under N2 was added (S)-2-methyl piperidine (Aldrich, 0.603 mL, 5.00 mmol) cautiously over 2 min. The vivid orange solution was stirred at RT for 18 h, then pyridine (0.404 mL, 5.00 mmol) and triphosgene (742 mg, 2.50 mmol) were added sequentially (CARE: exotherm on addition of triphosgene) and the orange solution stirred at RT for 4 h. Aqueous HCl solution (1M, 10 mL) was added and the mixture stirred vigorously until gas evolution ceased (30 min). The aqueous layer was extracted with DCM (10 mL), then the combined organics passed through a hydrophobic fit and concentrated in vacuo to leave the title compound as a dark red oil (745 mg, 92%). 1H NMR (300 MHz, CDCl3): 1.25 (3H, d, J 7.0), 1.42-1.77 (6H, m), 3.07 (1H, br s), 4.17 (1H, dd, J 13.8, 4.0), 4.62 (1H, apparent quin, J 6.3).

Provenance & Evidence